Electrical power transformer having means to prevent damage in shipment



Sept. 26, 1967 J. F. KOEPKE 3,344,381

ELECTRICAL POWER TRANSFORMER HAVING MEANS TO PREVENT DAMAGE IN SHIPMENT Filed Sept. 20, 1965 4 Sheets-Sheet 1 INVENTOR. J'o/m F, Hoe 0K5 Sept. 26, 1967 J. F. KOEPKE 3,344,381

ELECTRICAL POWER TRANSFORMER HAVING MEANS TO PREVENT DAMAGE IN SHIPMENT 4 Sheets-Sheet 2 Filed Sept. 20, 1965 IN V EN TOR.

John F 7(08/7/78 is. M

Sept. 26, 1967 IIIIII J F. KOEPKE 3,344,381

ELECTRICAL POWER TRMJSFORIVIER HAVING MEANS TO Filed Sept. 20, 1965 PREVENT DAMAGE IN SHIPMENT 4 Sheets-Sheet 5 95 INVENTOR. Z4 fa/777 F. Koe a/fe BY v .mm- 27 r 2.9% 3

25 I fitzl'orngf p 6, 1967 J F. KOEPKE 3,344,381

ELECTRICAL POWER TRANSFORMER HAVING MEANS TO PREVENT DAMAGE IN SHIPMENT Filed Sept. 20, 1965 4 Sheets-Sheet 4 IN VEN TOR.

United States Patent ELECTRMAL POWER TRANSFORMER HAVING MEANS TO PREVENT DAMAGE 1N SEHPMENT John F. Koepke, Bethel Park, lPa., assignor to McGraw- Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Sept. 20, 1965, Ser. No. 438,608 14 Claims. (Cl. 336-92) This invention relates to electrical power transformers and in particular to electrical power transformers that are shipped by rail.

Large kva. electrical power transformers usually have a core and coil assembly immersed in a dielectric fluid such as transformer oil within a four-sided metallic casing. The transformer core and coil assembly i very heavy because of the steel in the magnetic core and frame members and the copper in the windings, and when the transformer is shipped by rail the heavy core and coil assem bly may acquire high momentum and is subject to high impact forces both in the direction of shipment and at right angles thereto. For the purpose of preventing damage to the core and coil assembly during shipment, blocking and anchoring means are conventionally utilized to limit movement of the transformer core and coil assembly relative to the casing. Known anchoring and blocking arrangements limit movement of the core and coil assembly to from A" to 4 relative to the casing and have heretofore been adequate to prevent damage to the core and coil assembly during shipment by rail.

Experience gained in observing power transformers damaged in shipment indicates that articles being shipped are receiving greater impacts today both in the direction of shipment and at right angles thereto. The greater impacts in the direction of travel have been attributed to rougher handling in the railroad yards, whereas the greater vertical and lateral impacts are apparently caused by faster trains operating on rough tracks and poorly maintained railroad cars. The previously accepted A" to movement of the transformer core and coil assembly relative to the casing can no longer be tolerated under the greater impacts that power transformers are presently being subjected to in rail shipment.

Damage to the core and coil assembly during shipment could be prevented if the core and coil assembly were custom fitted with the tank to prevent relative movement therebetween, but this is impracticable from a cost and manufacturing viewpoint. The core and coil assembly and the tank are manufactured independently of each other and each has its own cumulative manufacturing tolerances. Such cumulative tolerances may result in considerable variation in overall dimensions with structures such as power transformers which may be up to forty feet in length. Cumulation of manufacturing tolerances makes the task of holding the parts to sufficiently exact size to prevent relative movement between the core and coil assembly and tank virtually impossible. Further, the custom fitting of core and coil assembly with the tank adds greatly to the cost of the transformer and requires a man to enter the transformer tank with loose metallic parts such as bolts, nuts, and washers which could cause electrical failure if inadvertently dropped and left within the tank.

It is an object of the invention to provide an electrical power transformer wherein relative movement between the core and coil assembly and the tank is eliminated.

It i a further object of the invention to provide such a power transformer wherein the movement-preventing connection between the core and coil assembly and the tank is accomplished with prefabricated standard parts which can be utilized in different kva. size transformers. Another object of the invention is to provide such a Patented Sept. 26, 1967 power transformer wherein the connection which eliminates relative movement between core and coil and tank can be made even when extreme variations in dimensions of tank and core and coil exist because of manufacturing tolerances.

Another object of the invention is to provide a power transformer wherein a connection can be made from the outside of the tank which eliminates all relative movement between core and coil assembly and tank, thereby avoiding the hazard of electrical failure which exists when a workman enters the tank with loose parts to make the connection.

Still another object of the invention is to provide a power transformer which can withstand, without damage to the core and coil assembly, twice the impact that prior art transformers were capable of withstanding.

These and other objects and advantages of the invention will be more readily apparent from the following detailed description when read in conjunction with the accompanying drawing wherein:

FIG. 1 is a front elevation view of a power transformer embodying the invention with the front tank wall removed to illustrate the internal construction;

FIG. 2 is a view taken along line 22 of FIG. 1;

FIG. 3 is a view taken along line 33 of FIG. 2; and

FIG. 4 is a view taken along line 44 of FIG. 1.

Referring to FIG. 1 of the drawing, a three phase electrical power transformer is illustrated as comprising a core and coil assembly 10 disposed within a four-sided metallic tank 11 which rests on a rigid base assembly 12. The core and coil assembly 10 may include a magnetic core 14 having three vertical winding legs 15 of steel leg laminations connected by upper and lower yokes 16U and 16L respectively of steel yoke laminations with mitered joints (not shown) between leg and yoke laminations. Elongated upper side frame channel iron members 18U may be disposed on opposite sides of the upper core yoke 16U and affixed thereto by insulated bolts 19, and similarly elongated lower side frame channel iron members 18L may be disposed on opposite sides of the lower core yoke 16L and aflixed thereto by insulated bolts 19. Cylindrical phase windings 22 surround each of the winding legs 15. The lower core yoke 16L and the lower side frame members 18L rest on laterally extending channel iron support members 24 which are supported on the bottom wall 25 of the tank 11 and are rigidly secured to the lower flange 26 of the lower side frame members 18L by bolts 27. Sheet insulation 28 (see FIGS. 2 and 4) may be disposed between the side frame members 18 and the core yokes 16. Tank 11 may have external hollow bracing, or reinforcing, bands 29 welded thereto extending around all of the vertical wall portions of the tank which provide space for expansion of gas within tank 11.

The leg and yoke laminations of magnetic core 14 may be of different widths to provide a generally cruciform cross section. Coil insulating blocks 301. may rest upon the upper flnage 31 of the lower side frame members 18L and upon horizontal extension plates 32L disposed in the plane of and welded to the upper flange 31 and supported by gusset plates 33 welded thereto and to the upper and lower flanges 26 and 31 of the lower side frame members 181., and a plurality of superimposed coil blocks 30L may be disposed beneath the windings 22 to prevent downward movement of the the coils 22.

The coil blocks 30L extend into the spaces in the generally cruciform cross section lower core yokes 16L. Similar insulating coil blocks 30U may be disposed against the upper surface of the windings 22. Steel clamping plates 34 are disposed above the coil blocks 30U, and upward movement of windings 22 under short circuit forces is prevented by studs 35 fitting at their lower end within cup-shaped members on the clamping plates 34 and engaging nuts disposed beneath the lower flange 36 of the upper side frame channel members 18U and also beneath horizontal extension plates 32U in the plane of the lower flange 36. The horizontal extension plates 32U are welded to lower flange 36 and to vertical gusset plates 33 which may be welded to the lower and upper flanges 36 and 37 respectively of the upper side frame members 18U. Superimposed insulating coil blocks 36 may be locked together by suitable means such as glue and wood dowels (not shown). Wedges 38- (see FIG. 1) of suitable insulating material such as fibre may be inserted between the windings 22 and the different width core yoke laminations, and the wedges 38 and the locked-together coil blocks 30 resist movement of the windings 22 relative to core 14 and to the side frame members 18 and increase the impact resistance of the transformer.

Steel top cross tie bars 39 may be afiixed to the upper flanges 37 of the upper side frame members 18U by bolts 46 or by welding. The top tie bars 39 are disposed above the upper core yoke 16U and resist short circuit forces and also vertical forces exerted against magnetic core 14 during shipment of the transformer.

The upper side frame members 18U and lower side frame members 18L extend beyond the outer core legs and beyond windings 22 and terminate closely adjacent but spaced from the tank end walls 41. Top blocking and tie-down assemblies 42 are disposed between the upper side frame members 18U adjacent each end thereof, and bottom blocking and guide assemblies 43 are disposed between the lower side frame members 18L adjacent each end thereof.

As best seen in FIGS. 2 and 3, each top blocking and tie-down assembly 42 may include a pair of spaced, vertically arranged, front and rear metallic plates 44 and 45 respectively disposed laterally of the upper side frame members 18U and secured by welding to a horizontal metallic bottom plates 46 and to the ends of a plurality of vertically disposed metallic rib plates 48 extending parallel to the upper side frame members 18U, thus forming a generally box-like upper blocking member 42. The end rib plates 48 are closely adjacent the upper side frame members 18U and are preferably secured thereto by large diameter bolts 49. A large diameter aperture 50 provided in each end rib plate 48 is in alignment with a similar large diameter aperture 51 in the web of the adjacent upper side frame member 18U, and a metallic pipe sleeve 53 is welded to each end rib plate 48 is surrounding relation to aperture 50. Large diameter shear pins 54, for example, three inch diameter steel pins, are inserted through the registering apertures 50 and 51 to securely connect the top blocking and tie-down members 42 to the upper side frame members 18U. The spaced apart upper side frame members 1-8U may have registering lifting holes 56 therein to permit lifting of the core and coil assembly 10, and the upper surfaces 57 of the rib plates 48 are inclined downwardly so that the rib plates 48 will not interfere with insertion of a lifting bar (not shown) through the registering lifting holes 56 in the upper side frame members 18U. The top flange 37 of the upper side frame members 18U may have cutout portions 58 to provide acess to the lifting holes 56.

Studs 35 at their lower end fit within cup-shaped members on metallic clamping plates 59' and extend through clearance holes in bottom plates 46 of the top blocking assemblies 42 and engage nuts disposed beneath bottom plates 46 to clamp metallic plates 59 (see FIG. 3) against coil blocks 30U and prevent movement of windings 22 in a vertical direction under impacts during shipping and short circuit forces. Sheet insulation 60 (see FIG. 2) may be diesposed between the magnetic core 14 and rear plate 45 of each top blocking assembly 42, and vertically extending insulating core blocks 61 of different widths may be disposed in the spaces between the generally cruciform-in-cross section core 14 and the upper side frame members 18U and the rear plate 45. The

4 core blocks 61 may be locked together by suitable means such as glue and wood dowels (not shown).

Upper'side frame members 18U are rigidly tied to the transformer tank 11 at both ends thereof, and this mechanical tie is accomplished from the exterior of the tank 11 after the core and coil assembly 10" is lowered into tank 11. Such solid mechanical tie between tank 11 and core and coil assembly 10' is achieved by heavy tiedown bolts 62 extending through clearance apertures 63- in tank end wall 41 and engaged within tapped holes in front plate 44 of each top blocking assembly 42 and having the bolt heads welded to circular metallic tiedown plates 64 which are, in turn, welded around the entire periphery thereof to the tank end wall 41 after the core and coil 10 is assembled into tank 11. In order to provide a rugged construction of high mechanical strength, heavy metallic support plates 65 are made integral with the tank end walls 41 by welding, the clearance apertures 63 are provided in the tank end walls 41 and in the heavy support plates 65, the tie-down plates 64 are welded around their entire periphery to the heavy support plates 65, and the tapped openings in front plates 44 of the top blocking assemblies 42 are formed by nuts 66 of substantial axial length inserted into an aperture in, and welded to opposite sides of, front plates 44, thereby providing a large number of threads in engagement.

The tie-down bolt assembly of integral tie-down bolts 62 and plate 64 is inserted through the clearance aperture 63 and engaged and tightened within nut 66 after the core and coil assembly 10 is lowered into tank 11, and tie-down plate 64 is welded to heavy support plate 65 after the tie-down bolt assembly is tightened and without entering tank 11. Preferably a continuous oil-tight /2 inch fillet weld is made around the outside edge of the tie-down plates 64 to secure the core and coil assembly 10 to tank end wall 41. It will be appreciated that since the upper blocking assemblies 42 are rigidly secured to tank 11 by tie-down bolts 62 and also rigidly secured to upper side frame members 18U by bolts 49 and shear pins 54, a solid mechanical tie is achieved between the core and coil assembly 10 and the tank 11 which prevents relative movement therebetween.

An asbestos welding gasket 68 is assembled between each tie-down plate 64 and the support plate 65 before they are welded together. If it becomes necessary to untank the transformer core and coil assembly in the field, the welds around the periphery of tie-down plates 64 are removed in the same conventional manner as in the case of welded covers for transformer tanks. The welding gaskets 68 prevent weld chips and arcs and burning flash from entering the tank 11. After the weld is removed from around the tie-down plates 64, the tie-down bolts 62 can be unscrewed from the nuts 66 attached to top blocking assembly 42, thus completing the disconnecting operation. It will be appreciated that the tie-down bolts 62 can be re-installed without entering the tank 11.

Each upper blocking assembly 42 is capable of withstanding a force of 2 /2 Gs in the direction of shipment, and since the core and coil assembly 10 is rigidly secured at both ends to the tank end walls 41, the top end of the core and coil assembly 10 is capable of withstanding a total shipping impact force of 5 Gs without movement of the core and coil assembly 10 relative to tank 11.

The lower blocking assemblies 43 serve to both guide the core and coil assembly 10 into its final position within tank 11 and to minimize movement of the lower end of the core and coil assembly 10 relative to tank 11. Each lower blocking assembly 43 includes a vertically disposed metallic rear plate member 70 positioned adjacent a core winding leg 15 and transverse to the lower side frame members 18L. Rear plate 70 is secured at its vertical edges by suitable means such as welding to vertical side plates 71 extending parallel to the lower side frame members 18L and at its top edge by means such as welding to a horizontal upper plate 72. Side plates 71 of the lower blocking assemblies 43 are secured by heavy bolts 74 to the lower side frame members 18L. Welded adjacent the lower end of rear plate 70 is a horizontally extending bottom guide bar 75 having a U-shaped aperture 76 therein facing the tank end wall 41 and adapted to receive an upstanding anchor and guide member 77 welded to the tank bottom wall 25 and extending transversely of the lower side frame members 13L. Gusset plates 79 are welded to the rear plates 70 of the lower blocking assemblies 43 and to the bottom guide bars 75 to reinforce the latter. Spaced vertical support plates 80 extending parallel to the side frame members 18L and welded to the tank bottom wall 25 abut against and are welded at their ends to the upstanding anchor and guide members 77 and to the tank end walls 41 and reinforce the anchor and guide members 77. Adjacent the top of each guide 77 is an upwardly inclined guiding portion 82 adapted to urge the core and coil assembly longitudinally of the tank 11, as it is being lowered into the tank, and into its final position wherein the U- shaped aperture 76 in bottom guide bar 75 snugly embraces guide and anchor member 77. Movement of the lower end of core and coil assembly 14) in a longitudinal direction relative to tank 11 is minimized by the guide bars 75 abutting against the guides 77, and movement in a transverse direction is minimized by the projections 83, which define the legs of the U-shaped apertures 76 in guide bars 75, abutting against the ends of guides 77.

Base channel sheet insulation 85 and core support blocks 86 (see FIG. 4) of insulating material may be disposed between the lower core yoke 16L and the transversely extending channel support members 24, and sheet insulation 89 (see FIG. 3) may be disposed between rear plate 70 of the lower blocking assemblies 43 and the core winding legs 15.

The bottom blocking assemblies 43 permit a slight but minimum movement of the lower end of the core and coil assembly 10 relative to tank 11, and the bottom blocking bars 75 engage the guides 77 practically instantaneously with the shipping impact and are able to withstand a force to 5 Gs in the direction of shipment. Consequently, the core and coil assembly 10 is braced to withstand a force of 10 Gs in the direction of shipment without substantial movement relative to tank 11.

Although the preferred embodiment has been described as having tie-down bolts 62 engaging tapped holes in the upper blocking members 42, it will be appreciated that in alternative embodiments short studs can be provided on the front plates 44 and the tie-down members which extend through apertures 63 in the tank end walls can have female threads engaging the studs.

While only a single embodiment of the inventions has been illustrated and described, many modifications and variations thereof will be readily apparent to those skilled in the art, and consequently it is intended in the appended claims to cover all such modifications and variations which fall within the true spirit and scope of the invention.

I claim:

1. An electrical power transformer comprising in combination, a metallic tank having opposed end walls, a transformer core and coil assembly within said tank including a magnetic core having a plurality of vertical winding legs connected by upper and lower yokes and surrounded by electrical windings, side frame members disposed on opposite sides of and afixed to the upper yokes and extending beyond said winding legs and said windings, blocking members disposed between said side frame members adjacent each end thereof and positioned adjacent said tank end walls, means for rigidly securing said blocking members to said side frame members, each tank end wall having a clearance aperture therein, each said blocking member having a tapped hole registering with one of said clearance apertures, and tie-down bolts extending through said clearance apertures and being engaged within said tapped holes and having metallic plates welded adjacent the head thereof exterior of said tank and said plates being larger than said apertures and closing said apertures and welded to said end walls of said tan-k around the periphery of said plates, whereby both ends of said core and coil assembly are rigidly tied to said tank and said transformer can resist impacts during shipment without movement of said core and coil assembly relative to said tank and the welding around the periphery of said plates can be removed and said bolts unthreaded to permit untanking of said core and coil assembly.

-2. An electrical power transformer in accordance with claim 1 wherein said side frame members are affixed to said upper yoke and including lower side frame members affixed to and disposed on opposite sides of said lower yoke and extending beyond said lower yoke and said windings, lower blocking members rigidly secured to and disposed between said lower side frame members adjacent each end thereof, and means including first and second pairs of releasably interengaging members for limiting movement of the lower end of said core and coil assembly relative to said tank in directions longitudinally and laterally of said side frame members and for permitting vertical movement therebetween, one member of each pair of said interengaging members being affixed to one of said lower blocking members and the other being affixed to the interior of said tank.

3. An electrical power transformer comprising, in combination, a metallic tank having opposed end walls, a transformer core and coil assembly within said tank including a magnetic core having vertical winding legs connected by upper and lower yokes and surrounded by electrical windings, side frame members disposed on opposite sides of and affixed to the upper yoke and extending beyond said winding legs and said windings, blocking members disposed between said side frame members adjacent each end thereof, each blocking member having side wall portions adjacent and parallel to said side frame members and an end wall portion transverse to said side wall portions and adjacent one of said tank end walls, said adjacent side frame members and side wall portions having registering openings therein, means including heavy metallic shear pins extending through said registering openings for rigidly affixing said blocking members to said side frame members, said end wall portions of said blocking members having tapped holes therein, metallic reinforcing plates welded to said tank end walls opposite said end wall portions and said reinforcing plates and said tank end walls having registering apertures therein opposite said tapped holes, tie-down bolts extending through said apertures and engaged within said tapped holes and having metallic plate portions secured adjacent the head thereof exterior of said tank and said plate portions being larger than said apertures and closing said apertures and being welded to said tank end walls around the entire periphery of said plate portions, whereby both ends of said core and coil assembly are rigidly tied to said tank and said core and coil assembly cannot move relative to said tank during shipment and the welding around said plate portions can be removed and said tiedown bolts unthreaded from said tapped holes to untank said core and coil assembly.

4. An electrical power transformer comprising, in combination, a metallic tank having opposed end walls, a transformer core and coil assembly within said tank including a magnetic core having a plurality of vertical winding legs connected by upper and lower yokes and surrounded by electrical windings, upper and lower side frame members disposed on opposite sides of and aflixed to said upper and lower yokes respectively and extending beyond said winding legs and said windings, upper blocking members rigidly secured to and disposed between said upper side frame members adjacent each end thereof and positioned adjacent said tank end walls, each tank end wall having an aperture therein, a pair of threaded interengaging male and female means for connecting said upper blocking members to said tank end walls, one of each pair of said means being on one of said upper blocking members and the other means extending through one of said apertures and having exterior of said tank a noncircular tool engaging portion and a radially extending portion larger than said aperture and closing said aperture and being welded around its entire periphery to one of said tank end walls, lower blocking members rigidly secured to and disposed between said lower side frame members adjacent each end thereof, means for limiting movement of the lower end of said core and coil assembly relative to said tank in directions longitudinally and laterally of said lower side frame members and for permitting vertical relative movement therebetween comprising first and second pairs of interengaging anchor members, one anchor member of each pair being secured to one of said lower blocking members and the other being secured to the interior of said tank, one anchor member of each pair having a U-shaped opening therein with the cross-piece of the U-shape transverse to said lower side frame members and the other anchor member having a portion complementary to and fitting within said U-shaped opening and abutting against the cross-piece and the leg portions of said opening, said anchor member secured to the interior of said tank having an inclined guiding surface along which the other anchor member of said pair can slide, as said core and coil assembly is lowered into said tank, until said U-shaped opening and said portion complementary thereto are in interengaging relationship, whereby both ends of the upper portion of said core and coil assembly are rigidly tied to said tank and said transformer can withstand impacts during shipment without movement of said core and coil assembly relative to said tank and the welding around said radially extending portions can be removed and said male and female means disengaged to untank said core and coil assembly.

5. An electrical power transformer comprising, in combination, a metallic tank having opposed end walls, a transformer core and coil assembly within said tank including a magnetic core having vertical winding legs connected by upper and lower yokes and surrounded by electrical windings, side frame members disposed on opposite sides of and affixed to the upper yoke and extending beyond said winding legs and said windings, a blocking member disposed between and rigidly affixed to said side frame members adjacent one end thereof, one of said tank end walls having an aperture therein opposite said blocking member, means including a threaded member extending freely through said aperture and engaging said blocking member for rigidly connecting said blocking member to said tank end wall, said threaded member having a radially extending portion exterior of said tank of larger diameter than and closing said aperture and being welded around its periphery to said tank end wall, whereby said core and coil assembly is rigidly tied to said tank and said transformer can resist impacts during shipment without movement of said core and coil assembly relative to said tank, said means being releasable from the exterior of said tank to disconnect said blocking member from said tank end wall when the weld around the periphery of said radially extending portion is removed.

6. An electrical power transformer in accordance with claim including blocking members rigidly afifixed to and disposed at both ends of said side frame members and wherein both said tank end walls have apertures therein and including a pair of said means for connecting said blocking members to said tank end walls and wherein each said blocking member has a tapped hole therein and said threaded members are bolts engaged within said tapped holes.

7. An electrical power transformer in accordance with claim 6 wherein said blocking members and said side frame members have registering holes therein and including heavy metallic shear pins extending through said registering holes and rigidly connecting said blocking members to said side frame members and wherein said side frame members disposed on opposite sides of said yoke have adjacent their ends registering lifting holes adapted to receive a lifting bar for lifting said core and coil assembly.

8. An electrical power transformer in accordance with claim 7 wherein said side frame members are disposed on opposite sides of said upper yoke and including lower side frame members disposed on opposite sides of and alfixed to said lower yoke, lower blocking members rigidly affixed to and disposed between said lower side frame members adjacent each end thereof, and means for limitmg movement of said lower blocking members relative to said tank in directions longitudinal and lateral of said lower side frame members and for permitting vertical relative movement therebetween, said means for limiting movement including first and second pairs of interengaging members slidable relative to each other in a vertical direction and one member of each pair being secured to one of said lower blocking members and the other member of said pair being afiixed to the interior of said tank.

9. An electrical power transformer in accordance with claim 8 wherein said one member affixed to said lower blocking member has a U-shaped aperture therein facing one of said tank end walls and the other member of said pair is upstanding and secured to the bottom wall of said tank and complementary to said U-shaped aperture and abutting against the portions of said one member defining the leg and cross-piece portions of said U-shaped aperture.

10. An electrical power transformer in accordance with claim 9 wherein said upstanding member has a guiding portion adjacent its upper end inclined upwardly toward one of said tank end walls and on which said one member can slide to urge said core and coil assembly longitudinally of said tank as said core and coil assembly is lowered into the final position within said tank wherein said upstanding member is received within said U-shaped aperture.

11. An electrical power transformer comprising, in combination, a metallic tank having a bottom wall and opposed end walls, a core and coil assembly within said tank including a magnetic core having vertical winding legs surrounded by electrical winding and connected by upper and lower yokes, upper and lower elongated channel iron side frame members disposed on opposite sides of and rigidly alfixed to said upper and lower yokes respectively and extending beyond said yokes and terminating adjacent said tank end walls, upper blocking members rigidly aflixed to and disposed between said upper side frame members adjacent each end thereof and having tapped holes therein opposite said tank end walls, said tank end walls having apertures registering with said tapped holes, tie-down bolts engaged in said tapped holes and extending through said apertures and having radially extending plate portions exterior of said tank larger than and closing said apertures and being welded around the entire periphery thereof to said tank end walls, lower blocking members rigidly afiixed to and disposed between said lower side frame members adjacent each end thereof and having U-shaped apertures in the surfaces thereof facing said tank end walls, and a pair of upstanding anchor members secured to said tank bottom wall and being complementary to and fitting within said U-shaped apertures and abutting against the portions of said lower blocking members which define the leg and cross-piece portions of said U-shaped apertures.

12. An electrical power transformer comprising, in combination, a metallic tank having opposed end walls, a transformer core and coil assembly within said tank including a magnetic core having a plurality of vertical winding legs connected by upper and lower yokes and surrounded by electrical windings, side frame members disposed on opposite sides of and afiixed to one of said yokes and extending beyond said winding legs and said windings, blocking members disposed between and rigidly aflixed to said side frame members adjacent each end thereof, each tank end wall having an aperture therein opposite one of said blocking members, threaded tie-down means extending freely through said apertures in said tank end walls and releasably engaging said blocking members and rigidly connecting them to said end walls and having radially extending portions exterior of said tank larger than said apertures and closing said apertures and being welded around their perpheries to said tank end walls, whereby both ends of said core and coil assembly are rigidly secured to said tank and said transformer can resist impacts during shipment without movement of said core and coil assembly relative to said tank, each said threaded means being releasable from the exterior of said tank to disconnect said blocking member from said tank end Wall when the weld around the periphery of said radially extending portion is removed.

13. In the combination defined by claim 11 wherein each said anchor member has a guiding surface inclined upwardly toward said tank end wall and on which said lower blocking member is adapted to slide toward its final position within said tank as said core and coil assembly is lowered into said tank and also including metallic plates extending parallel to said side frame members and disposed between said anchor members and said tank end Walls and welded to said tank bottom wall and reinforcing said anchor members.

14. An electrical power transformer comprising, in combination, a metallic tank having opposed end walls, a

transformer core and coil assembly mounted within said tank and including a magnetic core having a plurality of vertical winding legs connected by upper and lower yokes and surrounded by electrical windings, a frame assembly secured to the upper of said y'okes and extending laterally beyond the winding legs and the windings and including upper blocking members positioned immediately adjacent the tank end walls, each tank end wall having an aperture therein, a pair of threaded interengaging male and female means for connecting said upper blocking members to said tank end walls, one of each pair of said means being secured to one of said upper blocking members and the other means extending through one of said apertures and having exteriorly of said tank a tool engaging portion and a radially extending portion larger than the corresponding aperture and closing said aperture, and weld means circumferentially around the entire periphery of the radially extending portion and the adjacent tank end wall to securely attach the other of said means to said tank walls, said other means being removable only by removing of said weld means.

References Cited UNITED STATES PATENTS 2,351,097 6/1944 Boeringer 336-92 2,847,650 8/1958 Glassanos 336197 3,156,885 11/1964 Koza 336197 3,175,174 3/1965 Simmons 33692 LEWIS H. MYERS, Primary Examiner.

T. I. KOZMA, Assistant Examiner. 

14. AN ELECTRICAL POWER TRANSFORMER COMPRISING, IN COMBINATION, A METALLIC TANK HAVING OPPOSED END WALLS, A TRANSFORMER CORE AND COIL ASSEMBLY MOUNTED WITHIN SAID TANK AND INCLUDING A MAGNETIC CORE HAVING A PLURALITY OF VERTICAL WINDING LEGS CONNECTED BY UPPER AND LOWER YOKES AND SURROUNDED BY ELECTRICAL WINDINGS, A FRAME ASSEMBLY SECURED TO THE UPPER OF SAID YOKES AND EXTENDING LATERALLY BEYOND THE WINDINGS LEGS AND THE WINDINGS AND INCLUDING UPPER BLOCKING MEMBERS POSITIONED IMMEDIATELY ADJACENT THE TANK END WALLS, EACH TANK END WALL HAVING AN APERTURE THEREIN, A PAIR OF THREADED INTERENGAGING MALE AND FEMALE MEANS FOR CONNECTING SAID UPPER BLOCKING MEMBERS TO SAID TANK END WALLS, ONE OF EACH PAIR OF SAID MEANS BEING SECURED TO ONE OF SAID UPPER BLOCKING MEMBERS AND THE OTHER MEANS EXTENDING THROUGH ONE OF SAID APERTURES AND HAVING EXTERIORLY OF SAID TANK A TOOL ENGAGING PORTION AND A RADIALLY EXTENDING PORTION LARGER THAN THE CORRESPONDING APERTURE AND CLOSING SAID APERTURE, AND WELD MEANS CIRCUMFERENTIALLY AROUND THE ENTIRE PERIPHERY OF THE RADIALLY EXTENDING PORTION AND THE ADJACENT TANK END WALL TO SECURELY ATTACH THE OTHER OF SAID MEANS TO SAID TANK WALLS, SAID OTHER MEANS BEING REMOVABLE ONLY BY REMOVING OF SAID WELD MEANS. 